


And Madness is a Beautiful Irony

by PaperAnn



Series: PaperAnn's Kink Bingo 2017 Works [18]
Category: Supernatural
Genre: Alpha Castiel/Omega Dean Winchester, Alpha/Beta/Omega Dynamics, Angst and Feels, Canon Compliant, Castiel/Dean Winchester First Time, Episode: s09e03 I'm No Angel, Fallen Angel Castiel (Supernatural), Knotting, M/M, Newly Human Castiel, Nipple Play, Supernatural Kink Bingo 2017, Top Castiel/Bottom Dean Winchester, True Mates
Language: English
Status: Completed
Published: 2017-10-26
Updated: 2017-10-26
Packaged: 2019-01-22 06:51:12
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,122
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/12475836
Author URL: https://archiveofourown.org/users/PaperAnn/pseuds/PaperAnn
Summary: When Castiel’s grace was stolen, his life was in upheaval and he was fighting for survival.  Yes, there was a tidbit of information that hardly seemed relevant at the time, but when Cas finally meets up with the Winchesters (after a Reaper attacked him with an angel blade, no less) this curious fact becomes pivotal.Angels don’t have secondary genders, and when Cas fell, he assumed he’d take Jimmy’s beta status.  Except, now that he’s the only one in the vessel—now that it’s one-hundred percent Castiel—he has presentedalpha.Faced with Dean and overwhelmed by his alpha senses, this new biology and seeing the hunter as an omega for what feels like the first time, Castiel is faced with a realization.  Dean knows it right away, too.  They’re true mates, there’s no denying it, and it could be a wondrous thing to come out of Cas’ mortality.





	And Madness is a Beautiful Irony

**Author's Note:**

> Written for SPN Kink Bingo 2017  
> Square Filled: Nipple Play

“I…do not understand.”    
  
Castiel was sitting up straight on the edge of Dean’s bed in the bunker.  For _many_ reason's they'd raced back home after the debacle at April's.  All's well that ended well, but there was a lot of unfinished and....just _beginning_ business that had both Cas and Dean on the edge of their seats.  The drive back was...tense.  Sam the only voice of reason the entire trip.  Castiel only wished he could have gotten them their quicker, but he no longer had his wings.    
  
“Being human.  Well, I understand the basics.  I’ve managed, thus far.  I thought I finally had a grasp on things but when I saw you, everything changed.  I didn’t think anything of my vessel’s beta designation, it had been irrelevant.  Except now... it’s me and only me.  When I fell, I presented as an alpha.  And my alpha,” he slowly raised his gaze to meet Dean’s, “wants nothing more than to claim you, Dean.”

All right, that sent a full-body shiver down Dean’s spine and the words went right to his cock.  If he hadn’t been slick from Cas’ brand-spankin’ new scent before, he sure as hell was now.  God, his mouth was dry, but he needed to respond, needed to say _something_ because the fallen angel was unnerved.  
  
All of this, shit, Dean should have gotten to him sooner after the angels fell.  He hadn't even thought about Cas being human, and without his grace he'd present as _something_.  Something with animal-like instinct that angels were immune to.  That were looked down upon, because humans 'felt' too much, they were irrational and passionate because of their DNA.  Castiel was now one of them.  Dean should have known better!

Cas wasn’t fragile, but he was perplexed and searching for answers.    
  
Dean held those answers (fuck, just the thought of Cas wanting to claim him?  This was too good to be true!) and he took in a shaky breath.

“First off, the feeling’s mutual, so don’t freak out that much,” Dean had to ease his mind about what Cas was experiencing while he, himself, white-knuckled the wooden back of the chair.  “I, shit, Cas.  I don’t believe in true mates.  But I don’t know what the hell else this could be.  I’ve never, in my goddamn _life_ , wanted an alpha.  Not even once, their scents rub me the wrong way—but _yours_?”  He tried to control the whimper as it escaped his throat, “It’s…perfect.”

“True mates are very real, my Father created them, as rare as they may be.  Do you believe…?”  Cas left the sentence hanging in the air.  “I’ve…always been attracted to you.  I’ve always had feelings for you.  Ones that would be considered blasphemy to the other angels.  Yet falling shouldn’t have affected me this much.  This…urge, it’s taking me every ounce of will power not to move right now.”

Dean stared at him, the sweat beginning to bead up on his brow and he wiped it away in frustration.  “Wow.  What a great situation for a love confession.”

“It is.”  Castiel’s breath was coming out heavier, his pupils were dilated as he stared the omega down.  “I need to know.  Did you feel anything for me before this?  Anything at all?”

This was important to him, Dean could tell.  Cas didn’t want their inner animals to rule whatever was happening to them right now, he didn’t want their attraction to be from biology’s sucker-punch and nothing more.  Yeah, the omega understood that, which was why he made a joke about the ‘love confession’ part of it.

“Yeah, Cas,” Dean finally admitted, shifting awkwardly in his seat because, _yep_ , he was officially slick between his legs.  “Never thought to act on it.  Blasphemy, and all.  Thought you may hate me, ‘cause angels have got their own way of doing things.  And it doesn’t involve us and…well, sticky feelings.”

“I’d gladly condemn myself to be with you.”  Castiel whispered it like a prayer, “I believe I already have.  I may have lost my grace, but discovering we’re true mates may be worth more.”

So what, if his heart skipped a beat with those blue eyes boring into him with such honesty and urgency.  Dean always figured the alpha would be one for sweet nothings, at least that’s where his imagination took him.  In all Dean’s wet dreams there was a distinct possibility that sexy times ended with those kinds of tender moments.  Because it was so completely and utterly Cas.  The newly-reborn alpha was genuine, he was true, and the fact that he’d _willingly_ lose his wings to be with Dean—?

With a split-second glance, the omega noticed that the blood was gone, no longer flowing to Cas’ fists as he struggled to hold onto the edge of the mattress with white-knuckles.  His scent was filling the room, it was growing more and more intense by the second.  He wasn’t messing around, when he said that it was taking all his willpower to hold still.  And, God, it was a lovely sight.

A previous blank slate emanating bursts of sheer arousal, of need, of heady and desperate possession—those scents alone made Dean unintentionally whine.  He was responding to his alpha, yes— _his_ , like a bitch in heat.  It was only a matter of time until the dam broke.

“Cas—” Dean warned with his voice dropped in pitch, “We’ve gotta make a choice, here.  ‘Cause I’m holdin’ on by a thread and it’s about to snap.  If you don’t walk out of here, I’m pretty damn sure you know what’s going to happen next.”

It sounded like one word when Cas blurted, “Will you let me have you?” his voice husky and commanding.

“God, _yes_ —”

Dean launched from the chair, kicking it out from under him and sending it clattering to the floor.  And Cas was ready, meeting him halfway and tackling him down to the mattress, swinging his weight until he was pinned.  It knocked the wind from Dean’s lungs, because this was truly the power of an alpha.  The thrill rushed through him as they lingered—merely a breath apart—then Castiel descended on his lips.

Fuck, Dean had been imagining this for so long, and the make-believe fantasies didn’t hold a candle.  The alpha kissed him for all he was worth, licking the words from his mouth while he struggled with all the damn buttons on his flannel.

With a purely animalistic growl, Cas decided he’d had enough with the annoyance.  His need trumped everything else in his path and he ripped the shirt open—sending buttons flying haphazardly around the room.  And Dean didn’t have it in him to care.  It was just another barrier between them that needed to go!  Because his alpha was sucking at his pulse point, teasingly grazing his teeth along his neck, and it sent Dean's hips bucking off the bed.

Dean reached out and grabbed Castiel’s ass, just so he could haul their hips together and relieve the built-up friction that had his cock pulsing and thick.  When their pelvis’s collided, Cas moaned unabashedly and made the choice to get his omega naked.  Now.

He was swift and calculated undressing Dean, and the moment passed in a blur of thrown fabric and hot touches.  The next thing he knew was Cas’ hand between his legs, gliding through the slick that wasn’t just between his ass checks, but had gushed down between his thighs and was soaking the bed.  He would have been embarrassed if he wasn’t so desperate for Cas’ cock, for his knot—

Maybe this _was_ true mate shit.  Being completely lost in obsession, no longer able to think but ruled by the uncontrollable desire to be one—

“More, Cas, need more of you,” Dean clutched the alpha's shoulders and writhed underneath him.  “Next time, we can take it slow.  But I-I _can’t_ keep it together.  Need you more than anything, please, _please_ fuck me!”

The fallen angel nodded quickly, but knew enough to push his fingers into Dean’s needy, dripping ass to make sure he was loose enough not to hurt him.  But the omega’s hole was almost as hungry as he was, all but sucking the alpha’s fingers into his body as Dean tried to fuck himself against them, burying them deeper.

Cas’ breathing hitched, now scent-drunk and overwhelmed because he didn’t merely register his omega—he was picking up the scent of _mate_ : loud and clear.  He needed to please his mate, pleasure him, claim him…but the last part...it was still _too soon_.  Dean may never forgive him if he did such a thing without discussing it first.

With a sharp breath in, Cas took a step away to rip the remaining clothes from his own body.  All he wanted was for their skin to be pressed together, to feel the hot sweat now pouring form Dean, to feel him from the inside—

But his mouth, it _continued_  being drawn to Dean’s neck so he needed another target.  With a grin, having remembered the jokes, the comments, Dean had made in the past...Castiel set out to see if there was any truth behind them.

While he fingered Dean open, he slinked down the omega’s needy body and flicked his tongue over the top of his nipple.  Just a bare-minimum flash of wetness and then a slight breeze of air had Dean gasping and looking shocked with a dropped jaw.

“How did you...?!” he stared in awe, and Cas finally knew something he could dive into to distract himself from actually mating the omega.

Dean was whimpering and keening under him, more from the hard nubs being sucked on, rolled between Cas' lips and barely meeting the graze of teeth.  He had handfuls of Cas’ hair, keeping him steady on his chest, unabashedly showing his _full_ support Cas' friggin _fantastic_ mouth.  The way he worked his tongue and his lips...hell, being stretched open was basically an afterthought.

Castiel couldn’t help the graze of teeth, but instead of the neck, they brushed along Dean’s chest, sucking a mark into skin to prove this omega was his.  As he mouthed the blood to the surface, his free hand came up and teased the saliva-coated nipples, gliding across the nubs and Dean writhed wonderfully sensitive under his fingertips.

“You really do enjoy this, don’t you, Dean?” the alpha mused, proudly viewing his handiwork  _and_ the undone omega under him.

“Goddamn!” Dean blurted out as the alpha descended on him once more.  “Hell, you’re beautiful.”

Dean took a moment to splay his hands over the the alpha's muscled chest, his surprisingly chiseled abs, until he glanced down.  Fuck, now the omega was distracted; he found himself biting his own lip and captivated over the length and girth of Cas' heavy, hard cock.  They couldn’t be one soon enough.

“How do you want me?”  Dean demanded, his eyes raking over every inch of his stunning, sexy and powerful alpha.  “Tell me how you wanna knot me.”

With a wicked grin, Cas repeated, “You _want_ me to knot you, Dean?”

Before he could confirm with something that would have been a snarky retort, the omega found himself flipped onto his stomach with his ass cheeks spread wide open.  Yeah, he was exposed, but _God_ , it was addicting in that dangerous, adrenaline-junkie way.  His normally timid Angel-of-the-Lord was spreading him wide open, man-handling him into presenting?

He felt the thickness of Cas’ cock head circle his rim, paired with the question, “Are you mine?  Tell me you’re mine.”  It was throaty and erotic, and he was using it as bait before he pushed in.

“Y-yeah,” Dean confirmed with quivering, pleading breaths.  “Fuck me and claim me with your cum, Cas.  Fill me full, now, I’m _yours_.  A-Always been yours.”

Dean felt every single inch when the alpha slid in.  He felt it because of Cas’ alpha cock, because it was so spur of the moment and they’d been driven insane without waiting, but more than that—Dean felt this acute completion.

With hands digging into Dean’s hips, Cas growled out, “ _My_ omega, all mine,” as he began to rock his hips.

And Dean couldn’t agree more.

Jesus—they just _fit_.  There was this sense of right, this light bulb, and it was a cosmic joke that his true mate had to _fall from Heaven_ for Dean to even find him!  But he sure as hell wasn’t complaining more.

And right now, oh, Cas wasn’t holding back.

For a novice, the way he pounded into him was rocking Dean’s world.  He was seeing stars when the alpha brushed Dean's prostate and learned very quickly that he could use that angle to make the omega sing.  

It was fast and furious, like sex during a heat or a rut, but it was for a completely different reason.  They’d found each other.  It was so much heavier than a cycle, this was it—this was the change-all, end-all of what people spent their whole goddamn lives searching for.  And coming together like this, for the first time as true mates, it was too much.

“Cas, I’m gonna—” Dean gasped out, trying to give some warning with the remaining breath in his lungs.

“Cum for me,” the alpha demanded, his hips pumped while his hands flew to both wrap around Dean’s cock and to roll his nipples again, Cas’ secret weapon— “I’m gonna knot you, fill you to the brink.”

“Yes,” Dean moaned out at the thought, but more than anything the onslaught of sensation.  He tried to push meaning, urgency and dedication into his words, but he was so caught up when he said, “Wanna milk you dry—”

And, holy hell, Cas _delivered_.

After he left Dean a euphoric, pleasure-wrecked, sobbing mess after his orgasm, Castiel continued to pound into him.  Exchanging Dean’s now-sore and throbbing nipples instead of leaving a mating bite had worked, but the desire was there.  And Cas surely could leave some of himself with Dean on the inside.  Stretch him to the limits.  Make sure the omega couldn’t walk straight for the next week.  And Dean loved _every second_ of it.

God, it was passionate, it was urgent and more than anything...when they finally collapsed into his bed—both dizzy and weary—Dean could scent the love behind that true mates bond.  It was something the omega  _never_ thought he could have…and he’d been given the chance.  He’d been given a gift, in the most unlikely of ways, and even before all this?

Fuck yeah, he’d loved the angel.

Now he just had a valid reason to say it.

He craned his neck back to where Cas was mouthing his shoulder and said in a hushed tone, “I’m happy this happened.  I know you’ve been though some shit, that you lost something, a huge part of yourself.  But I’m gonna take care of you.  Promise.  I love you.”

Thankfully, Castiel’s scent was aglow with sheer joy as he smiled contentedly at his mate and nodded.  “I love you, Dean.  And thank you.  It’s been a...an extremely difficult transition, but with you?  It’s worth it.”

Everything seemed to be turning around, after so much shit had been thrown their way, things were looking up.

Even when the three were gathered in the war room and Cas admitted that he’d fucked the Reaper who'd stabbed him with that goddamn angel blade, Dean saw red for all of two seconds before he remembered…this alpha _was his_.  The fallen angel saw it in his eyes, tried to backtrack but the damage was already done.  Dean smiled to assure him it was in the past.  Sam laughed at the story, even though not a damn part of it was funny.

But having the three of them together was so refreshing, having his mate here with him by his side?  Having his brother on the mend?  Everything was coming up roses!

That was, until Ezekiel’s ultimatum absolutely _destroyed_ Dean and any hope he could have had.

The news that Castiel was a risk, that the angels would continue to hunt him down and he was too dangerous to keep at the bunker floored the omega.  Dean had fought, he’d fought like fucking hell for Cas, he wasn't just his mate, he was the love of his life!  But when Ezekiel said the words: that he  _would_  leave Sam’s body—leave his brother for dead—

Dean was in shambles, he didn’t know what to do, because it was a choice between his brother and his true mate.

And…Sammy.  Sammy won out, every time.

After Cas and his revelation, after their end-all, happily-ever-after discovery and _finally_ accepting they truly were meant to be…  
  
Dean had to fucking confront his true mate and kick him out.

He thought he’d known heartache before, but the look of Cas crumbling before his eyes, knowing that he’d done this?  Knowing that he had shattered the alpha—Dean didn’t know if he could forgive himself for this.  No matter what kind of life-saving reason for his brother, or his intentions, he'd hurt Cas in ways that he'd _kill_ another for doing so.  Except, the one inflicting the pain was Dean, himself.

Dean waxed words of “we’ll make it work,” and “this is temporary” but it did nothing to dull the tearing internal agony of his heart.  All Dean wanted to do was explain everything to Cas, spill the situation about Ezekiel and the fact that Sam was being held together by safety pins and band-aids on the inside, but he _couldn’t_.  All he could do was pull the alpha close, kiss him in the most gut-wrenching goodbye and tell him to stay safe.

Even though it should have been _Dean_ to keep him safe.

He wouldn’t deny that tears fell that night after he'd killed a fifth by himself and passed out from the booze.  The omega was already in mourning, he didn’t even get the opportunity to wrap around his mate and fall asleep, listening to Cas' human heartbeat as they slept, nestled together.  Maybe he could fool himself with the lies he told his alpha.  With the promises of "we'll make it work" and "this is temporary," because Dean wouldn't be able to make it if he didn't have something to believe in.  
  
It made him wonder...would Ezekiel have forced Castiel out if they had mated?  Would he be so heartless?  Did they miss their chance?  Dean wasn't wasting another opportunity, the next time he saw his mate, Cas would be just _that_.  Then no one would be able to rip them apart again.  Dean would make damn sure of it.


End file.
